1. Field of the Invention
The present invention generally relates to binder/aggregate/container systems for effecting road surface and/or bridge joint repairs. More specifically this invention relates to those binder/aggregate/container systems that employ polymeric materials e.g., petroleum-derived asphaltic materials, synthetic polymers such as those of propylene, ethylene-propylene copolymers, butylenes copolymers and the like—as well as mixtures thereof—as binder materials.
2. Description of Related Art
In the road surface and/or bridge joint repair industry, those binder components and aggregate components used to repair cracks, potholes and bridge joint breaks are usually shipped to a job site in one of two ways. In the first way, a load (often a pallet-sized load) of individual packages of a binder material are shipped to a job site. Similarly, a load (again, often a pallet-sized load) of individual packages of one or more aggregate materials are shipped to the job site. Ideally, a certain number of packages of binder material and a certain number of packages of the aggregate material are removed from their respective pallets, unwrapped and their contents placed in a melter unit. The certain numbers of respective packages is intended to create a mixture having a certain desired ratio of binder material to aggregate material. Unfortunately, job-site mistakes are made in getting the right number of packages of each type of ingredient into the melter. This results in binder material/aggregate material repair compositions that have too much or too little of the binder material relative to the aggregate material.
The second way that asphaltic components and aggregate components are shipped to a job site is in the form of packaged blocks of a mixture of the binder component(s) and the aggregate component(s). A desired binder to aggregate ratio can thereby be maintained. These mixture blocks are, however, relatively expensive to make and use. This follows from the fact that the binder component must be melted at the factory (at a considerable fuel expense) and the aggregate component thoroughly mixed into the melted binder material. The resulting binder material/aggregate material mixture or composite is then placed in containers where the binder component cools and solidifies. Those skilled in this art also will appreciate that package materials have been developed that, in effect, eliminate the need to remove or dispose of the outside container. One type of such a package is disclosed in, e.g., U.S. Pat. Nos. 5,452,800 and 5,307,608. They teach binder packages employing thin, meltable, polypropylene films as the sole containment means—and methods for their manufacture.
U.S. Pat. No. 5,992,628 teaches an binder/package system comprised of an binder composition surrounded by a container made of a meltable material. That is to say that the container is melted along with the binder when the package is put into those gas fired melter units typically used at job sites. The container is made of a composition comprised of about 40-90% of an asphaltic material and about 10-60% of a synthetic polymer such as propylene, ethylene-propylene, methacrylates and the like. The container has various physical features e.g., handles, breakage channels for dividing the binder into fractional submits such as one half, one quarter and so on.
U.S. Pat. No. 5,765,686 also teaches packaging binder materials in consumable packages made of binder/polymer compositions. Such packages are provided with fraction creating (e.g., one half, one quarter, etc.) breakage line indentations molded into the material from which the composition is made. A thin, meltable, polymer film (e.g., polypropylene), is used to provide outside protection for the package.
U.S. Pat. No. 2,988,207 (“the '207 patent”) teaches a package system for ready mix concrete. Its sand, or sand and gravel, components (or other materials) are contained in a paper outer paper bag. A smaller, moisture sealed, plastic bag, filled with dry cement, is placed inside the paper bag. The contents of the outer bag (sand, gravel) as well as the cement contents of the inner bag (cement) are premeasured to their proper proportions. They are mixed with water at the job site to produce a concrete forming composition.
U.S. Pat. No. 4,678,363 teaches a road repair truck having an aggregate hopper and a binder hopper. The aggregate hopper has a conveyor and a discharge chute for receiving the aggregate and directing it downwardly. A discharge outlet on the chute dispenses the aggregate to a pothole, etc. while a binder composition is sprayed on to the aggregate as it is being dispensed. To this end, the chute is provided with a rotatable hollow shaft that extends below the outlet of the aggregate discharge chute. A projection is mounted on the periphery of the hollow shaft in order to better mix the aggregate that is moving downwardly through the discharge chute. A plate device is attached to the hollow shaft to make the aggregate swirl and flare outwardly as it drops downwardly to the road surface. Again, the binder is sprayed on the swirling aggregate just as it leaves the discharge chute (i.e., but before it reaches the roadway).
U.S. Pat. No. 1,546,185 (“the '185 patent”) teaches a road repair vehicle having partitioned road repair ingredient sections. A heating box is positioned between the partitions. Heat from a heater box is circulated through a casing system in order to heat the as yet unmixed road repair materials.
U.S. Pat. No. 5,333,969 teaches an automated repair vehicle in which computer controls direct the mixing of desired amounts of various road repair composition ingredients.
U.S. Pat. No. 5,988,935 teaches a road repair vehicle having a self-contained heating box. The binder used by this vehicle is not heated separately from the aggregate.
U.S. Pat. No. 1,512,389 teaches a road repair vehicle having different compartments such that all of the road repair compositions are heated separately.
U.S. Pat. No. 4,511,284 (“the '284 patent”) shows a pothole repair unit in which asphalt is heated separately from the separate aggregate. The heated aggregate particles are then coated with the heated asphalt.
These patents fall into two broad categories (1) those devoted to generalized packaging methods (for binder and aggregate materials, as well as for other materials such as concrete ingredients) and (2) those devoted to binder material (e.g., asphalt) dispensing vehicles. The packaging method patents (e.g., the '628 patent and the '686 patent) generally teach use of “consumable” containers. That is to say an asphalt/polymer container and its asphalt or asphalt/polymer contents are thrown in a melter as a unit. These containers also may be partially divided or compartmentalized. This is done for the purpose of breaking these containers (and their binder contents) into smaller sizes (e.g., one half, one quarter, etc.) at a job site. It should be specifically noted however that these compartmentalized binder packages do not contain two distinct kinds of ingredients (e.g., a separate and distinct binder ingredient, and a separate and distinct aggregate ingredient, etc.), but rather contain a body of a composite material (a solidified mixture of asphalt/polymer and aggregate).
The '207 patent teaches a container having two distinct compartments containing two different materials. This system is not, however, concerned with asphalt related products. Rather, it is concerned with packaging a cement/sand (or sand and gravel) system that will be used to make concrete. The cement absolutely can not be allowed to come into contact with moisture before it is mixed with the aggregate. Hence, it is placed in a tightly sealed, moisture proof, plastic bag that resides in a second, layered paper, bag that contains the sand (or sand and gravel) ingredient(s). At the time of use, the two bags are broken, the materials are mixed with each other and water is added to the mixture to produce a wet concrete mixture that is poured into a form and allowed to dry in that form.
Thus, none of the above noted patents teach a binder/aggregate container system that has a binder material component (such as an asphaltic/polymer composition) that substantially constitutes a separate and distinct material relative to an aggregate component that also resides in the same container. Such binder/aggregate compartmentalization is found only in those patents concerned with asphalt laying machines. These patents generally teach heating the separated ingredients at the same time, although not necessarily to the same degree. For example, the vehicle described in the '363 patent has a first hopper for containing an aggregate material and a second hopper for containing an additive material. Similarly, the vehicle described in the '284 patent shows a hopper that holds and dispenses aggregate, while a separate and distinct tank holds a road patching, asphaltic material. The '185 patent teaches a system wherein a heater is placed between a bituminous material tank and an aggregate hopper. The heater is used to heat these two materials in a differential manner. The system is particularly concerned with assuring that the aggregate component is sufficiently heated.
In contrast with the teachings of all of the above patents, applicant has found that if a body of binder material such as an asphaltic and/or synthetic polymeric material is introduced into a melter—as a substantially distinct body (as opposed to being in the form of a binder/aggregate mixture)—it will more readily melt relative to a homogeneous mixture or composite of the same binder material and the same aggregate material. Comparatively speaking, applicant has found that road and/or bridge repair processes based upon throwing a substantially separate and distinct body of binder material and a substantially distinct body of aggregate into a given melter unit is (especially, from a heat efficiency point of view) a better process than throwing a body of thoroughly mixed or otherwise composited binder and aggregate into that same melter unit under comparable heating conditions. Assuring that these two distinct materials are used in the proper proportions adds to the utility of the product created by subsequently thoroughly mixing these two ingredients. Thus, applicant has developed road repair systems or kits that serve to assure that a binder ingredient is introduced into a melter as a body that is substantially distinct from an aggregate ingredient body that is also introduced into that same melter unit. In one particularly preferred embodiment of this invention, the distinct body of aggregate material is embedded in a body of binder material. In another particularly preferred embodiment, a meltable bag is first placed in a container of a defined size and configuration such as a box having a square or rectangular cross sectional configuration. A predetermined amount of aggregate is then put into the meltable bag. Thereafter, a predetermined amount of the binder is placed on the aggregate. The binder can be in the form of one or more solid blocks or, in the alternative, the binder is in a fluid, that is to say liquid or semi-liquid state, so that it can be poured over the top layer(s) of the aggregate particles and then allowed to cool, and hence solidify. In another somewhat less preferred embodiment, the binder is placed in the meltable bag first and the aggregate placed over the binder. In either case, however, there should be a fairly well defined body of aggregate-free binder and a fairly well defined body of binder-free aggregate. These kits also will serve to assure that proper proportions of aggregate and binder are employed.